One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10)(11,18)(12,20)(13,15)(14,17)(16,22)(19,23)(21,24)(25,26)(27,37)(28,33)(29,34)(30,35)(31,36)(32,40)(38,39) involution — undirected(1,2,5,6)(3,7,4,8)(25,27)(26,32)(28,38)(29,39)(30,34)(31,40)(33,35)(36,37)(1,3,5,4)(2,7,6,8)(9,11,14,13)(10,15,17,18)(12,19,22,21)(16,23,20,24)(25,26)(27,37)(28,33)(29,34)(30,35)(31,36)(32,40)(38,39)(1,3,5,4)(2,7,6,8)(9,12)(10,16)(11,19)(13,21)(14,22)(15,23)(17,20)(18,24)(25,28,31,34)(26,33,36,29)(27,38,40,30)(32,35,37,39)(1,3,5,4)(2,7,6,8)(9,13,14,11)(10,15,17,18)(12,21,22,19)(16,23,20,24)(25,29,31,33)(26,34,36,28)(27,39,40,35)(30,37,38,32)(1,4,5,3)(2,8,6,7)(9,10)(11,15)(12,16)(13,18)(14,17)(19,23)(20,22)(21,24)(25,30,31,38)(26,35,36,39)(27,34,40,28)(29,32,33,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.